Outdoor advertising company Ad-Air has set a world record for the largest advertising banner after launching its first mega advertising site at Dubai airport.

The advert, for Sorouh Real Estate, covers more than 20,000 sq m - more than two football pitches - and is viewed from the air by arriving and departing plane passengers.

The site was independently verified by an inspector from the Guinness Book of World Records and designated as the record holder for the new category of "world record for banner size".

Stephen Jones, the managing director of Ad-Air Middle East, said the sheer scale of the ad was "unbelievable".

"It is fitting that our first advertiser should be a real estate company, given the current explosion of property development in the region," he added.

"The Ad-Air site offers an unprecedented marketing opportunity for any brand wishing to put its stamp on Dubai and immediately make an impression on visitors."

Sorouh is using the site as a branding exercise for four months. It plans to fill the banner with a million faces from around the world in the new year as part of a charitable campaign to raise money for the United Arab Emirates Red Crescent.

Members of the public are invited to upload their photograph free at sorouhfaces.com. For each face the company will donate $1 (49p) to the humanitarian organisation.

The amount Sorouh paid is undisclosed, but the site forms part of a multimillion-pound brand awareness campaign. Ad-Air has previously said the price is £40,000 to £80,000 a month depending on location, with copy changing every six to 12 months.

The site in Dubai is the first of an international network of mega advertising at airports planned by Ad-Air. It will be seen by an estimated 14 million people.

The company, which is backed by £5m in private equity finance, has rights to 30 airports, including London Heathrow, Paris Charles de Gaulle, Los Angeles International, Chicago O'Hare and Tokyo Narita.

Each airport will have a maximum of four sites. Ad-Air intends to calculate impact on the basis of average numbers of annual passengers per runway, the number of flights during visible periods, average plane capacity, and visibility from window seats. Ad-Air indicated it would launch at least four new sites in early 2008, two in Europe and two in the US.

However, media agencies and advertisers in the UK are generally unenthusiastic about the concept, arguing it is expensive and unaccountable.

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